I'm pretty sure I'm done adding levels now with the final being level 13. There's just only so much you can do without modifying the program post-compile. I could make things more complicated, but it would just be the same operations repeated. I figure by time you might get to the end levels, you've pretty much seen it all so it shouldn't be that much harder, maybe just more time-consuming. There is now a directory called 'solutions'. Right now it only contains the solutions for levels 0-2. I will add more once I do the analysis of their disassemblies. Now that it's finished and fully tested, I should have more time for the analysis, so stay posted for solutions if you need help with any of it.
There is now also a library of C functions I made if you feel up to making your own crackme challenges, hopefully they can be useful for that.
!!!! NOTE !!!!!!
If you are using any version that was up on here before 09-10-2024, do not bother using it, just download the new one. The newer one will have this comment at the top:
"Major overhaul to fix several different problems Complete Date: 09-10-2024"
Due to the mistakes made in it, you can actually end up getting the correct password, but it won't be correct in the 'strcmp' by time it goes through the rest of the code. This is an embarassing mistake, and apologies to anyone who used this program before that date, as they may have wasted a lot of time trying to solve something that didn't even work properly. (>_<)
!!!!!!!!!!!!!!!!
CORA: Crackme Originating Randomizing Automator
For generating crackme challenges of different difficulty levels.
When studying software reverse engineering, I came across the concept of crackme challenges. I found many of them, but when searching for a program that generates them, it seemed to turn up nothing. So, that's exactly what I made.
You enter the name of the resulting executable, and the difficulty level (0-13). Then, it generates a prng password with varying size, along with possibly prng generating different sets of values for the operations done on the input password and sets up the C source code according to the difficulty level. Finally, it outputs the source code and compiles it with gcc. Then, the idea is to use whatever tools you wish to RE the executable and get the correct password to input. Obviously, you could just change the jump conditional to a jmp straight to the win message, but this defeats the whole point of the challenge. Do what you want, though...
It uses gcc by default, but of course you could change this to any other command line C compiler of your choice. If you want to see the source code first without compiling it, you can also just comment out that 'os.system(gcc __)' line.
By default, it also does not delete the source code file. If you are serious about practicing reverse engineering, you may want to uncomment the 'os.system(rm -i ___)' line so it deletes that file, then you can avoid the temptation of peeking at the C source which does make it too easy to solve.
TIP: Most levels build on the previous levels, so if you analyze the disassembly for one and keep good notes, it will often help when you start to recognize the same instruction patterns in the later levels, possibly saving a lot of time.
This program will not have any kind of license on it, so you are free to do whatever with it. I hope someone gets something out of this, enjoy! --stringzzz